H5

In Australia, H5 is a hazard level for treated lumber that indicates the level of protection against decay and insect attack. The H5 treatment is a heavy-duty treatment and is suitable for use in ground contact applications where the timber is exposed to severe decay and insect hazards, such as in marine environments.

The H5 treatment process involves treating the lumber with a preservative that contains copper, azole fungicides, and a co-biocide. This treatment provides protection against decay fungi, borers, termites, and marine borers.

H5 treated lumber is commonly used for a range of outdoor applications, including marine piling, sea walls, and bridge timbers. It is important to note that H5 treated lumber is not suitable for use in applications where the timber is in direct contact with food or drinking water. For those applications, a food-grade treatment would be required.